Catalytic process fob the prepara



Reissued Sept. 5, 1950 UNITED STATES PATENT OFFICE CATALYTIC PROCESS FORTHE PREPARA- 'I'ION OF ACRYLIC ACID NITRILE Peter Knrtz,Leverkusen-Bayerwerk, Germany; vested in the Attorney General of theUnited States 22 Claims.

In Germany July 10, 1939 Matter enclosed in heavy brackets appears inthe original patent but forms no part of this reissue specification;matter printed in italics indicates the additions made by reissue Thisinvention relates to a process of preparing acrylic acid nitrile andcomprises bringing acetylene together with hydrocyanic acid into contactwith a suitable catalyst.

It is known that by passing acetylene into an aqueous acid reactingsolution of cuprous chloride and alkali chlorides or ammonium chloride,vinyl derivatives are obtained.

Now my present invention is based on the perception that catalysts forbringing about those addition reactions of acetylene which result invinyl derivatives thereof also effect the addition of hydrocyanic acidon acetylene. Briefly stated my process consists in bringing acetylenetogethe with hydrocyanic acid into contact with an acid reactingsolution of cuprous chloride as a catalyst. It may be pointed out thatall variations in the catalyst as they are known in the formation ofvinyl derivatives from acetylene may be advantageous in my presentprocess. Thus, for instance, an aqueous acid reacting catalyst ispreferably employed. prepared from cuprous chloride and a. salt of theclass consisting of ammonium, amine and alkali salts. It is advantageousto add to the catalyst copper powder in order to maintain the coppersalt in the monovalent state as cupric copper may cause undesired sidereactions. The acid reaction of the catalyst is attained by adding a.strong acid such as hydrochloric acid, hydrobromic acid, sulfuric acidor phosphoric acid and it is preferable to adjust the pH to about 6,however, a catalyst having a stronger acid reaction may also beemployed. A suited catalyst may be composed from 45.5 parts of cuprouschloride, 24.5 parts of ammonium chloride, 42 parts of water and 2.8parts of concentrated hydrochloric acid. Equivalents may be used for thechemicals named and the proportions of the constituents may be varied.

The reaction may be carried out at temperatures between -200 C., but itis preferable to hold the temperature at about 80 C. when working underatmospheric pressure. The acetylene and the hydrocyanic acid may bepassed in at atmospheric and higher pressures. It is advantageous towork with an excess of acetylene, for instance, one part of hydrocyanicacid and parts of acetylene. Obviously, the reaction may be carried outin a continuous process.

The following examples illustrate my invention 2 without, however,restricting it thereto the parts being by weight.

EXAMPLEI 20 parts of anhydrous hydrocyanic acid are dropped at C. into amixture consisting of 300 parts of cuprous chloride, parts of ammoniumchloride, 5 parts of COTICL rated hydrochloric acid, 10 parts of copperpowder and 400 parts of water which has been heated to 86" C. in anitrogen atmosphere while stirring and passing in acetylene in exc ss.The reaction vessel is connected with a condenser. Water and an oilysubstance distil the latter forming the upper layer. When allhydrocyanic acid is dropped in the reaction mixture is heated to 103 C.with further passing in acetylene. Further amounts of water and oildistil. The oily distillate (27 parts) is separated from the aqueoussolution, which contains unchanged hydrocyanic acid. dried anddistilled. At first some vinyl acetylene distils, finally the acrylicacid nitrile. A residue consists of divinyl acetylene. The catalyst maybe used for several crops. The distilled water may be reconveyed in thecatalyst.

EXAMPLE 2 40 parts of a mixture consisting of equivalent amounts ofacetylene and hydrocyanic acid are added at room temperature to thecatalyst which has been mentioned in Example 1. The temperature risesslowly, but is not permitted to rise above about 30 C. The acetylene iscompletely absorbed. The reaction mixture is allowed to stand forseveral hours and then slowly heated. At temperatures between 70 C. and103 C. a. mixture consisting of acetylene, hydrocyanic acid, acrylicacid nitrile and water distils. The acrylic acid nitrile separates as anoil which forms the upper layer. It may be worked up as stated inExample 1.

EXAMPLE 3 1170 parts of cuprous chloride and 630 parts of ammoniumchloride are heated to 80 C. with exclusion of air together in 1010parts of water with the addition of 43 parts of concentratedhydrochloric acid and 36 parts of copper powder. All components dissolvewith the exception of copper. parts of acetylene and 13.5 parts ofhydrocyanic acid per hour are passed in at a temperature of 80 C. Theescapin vapors are at first precooled in a condenser in order toseparate the water. Then the vapors are dried for completely removingthe water and subjected to a low cooling at '70 C. The noncondensedportion consists practically of acetylene and is reconveyed in the cyclewith addition of 15 parts of acetylene what corresponds to the convertedportion. Likewise 13.5 parts of hydrocyanic acid must be introduced inthe cycle per hour, however, this amount may be partly recovered fromthe condensate.

The condensate which is collected during several hours is distilled. Ityields at first some acetylene. then vinyl acetylene and hydrocyanicacid, finally as main product acrylic acid nitrile. The yield is(calculated on the consumed amount of hydrocyanic acid) about 90% and(calculated on the consumed amount of acetylene) about 70%.

With similar success the hydrochloric acid may be replaced by otheracids, for instance, sulfuric acid, phosphoric acid or hydrobromic acid.Furthermore the ammonium chloride may be replaced by salts of ammoniawith other acids (for instance ammonium sulfate) as well as by salts ofamines.

EXAMPLE 4 450 g. of cuprous chloride are heated together with 200 g. ofsodium chloride in 525 g. of water with the addition of 15 g. of copperpowder at 80 C. Partial solution occurs. At 80 C. and at mosphericpressure 100 liters of acetylene and 5.3 g. of hydrocyanic acid per hourare passed in. The consumption of acetylene amounts to 42 liters perhour. It is substituted as stated in the preceding example. Likewise 5.3g. of hydrocyanic acid per hour must be conveyed in the cycle. Whenworked up as stated in the preceding example 5 g. of acrylic acidnitrile per hour are obtained.

EXAMPLE 5 545 g. of cuprous chloride and 435 g. of ammonium chloride areheated to 80 C. in 500 g. of water with the addition of 20 g. of copperpowder. Clear solution occurs with exception of the copper. When 100liters per hour of acetylene are passed in 4 liters per hour areconsumed. Besides 3.8 g. of hydrocyanic acid per hour were added. Whenworked up as stated in Example 3, 4.8 g. of acrylic acid nitrile perhour are obtained.

EXAMPLE 6 Acetylene with a speed of 7000 liters per hour is passedthrough a catalyst prepared from 45.5 kg. cuprous chloride, 24.5 kg. ofammonium chloride, 42 liters of water and 2.4 liters of concentratedhydrochloric acid at a temperature of 80 C. To the acetylene are added530 g. of hydrocyanic acid per hour. The escaping vapors are separatedby cooling as stated in Example 3. The acetylene is conveyed in a cycleand the consumed part and the hydrocyanic acid are substituted. 600liters of acetylene per hour are consumed, which must be substituted,908 g. of pure acrylic acid nitrile per hour are obtained.

I claim:

1. Process for the manufacture of acrylic acid nitrile which comprisesbringing acetylene togather with hydrocyanic acid into contact with anaqueous acid reacting solution of cuprous chloride said solutioncontaining also a salt of the class consisting of ammonium, amine andalkali salts.

2. Process for the manufacture of acrylic acid nitrile which comprisesbringing acetylene together with hydrocyanic acid into contact with anaqueous acid reacting solution of cuprous chloride said solutioncontaining also copper powder and an ammonium salt.

3. Process for the manufacture of acrylic acid nitrile which comprisesbringing acetylene together with hydrocyanic acid into an aqueoussolution prepared from cuprous chloride and a salt of the classconsisting of ammonium, amine and alkali salts.

4. Process for the manufacture of acrylic acid nitrile which comprisesbringing acetylene together with hydrocyanic acid into an aqueousreacting solution prepared from cuprous chloride and a salt of the classconsisting of ammonium, amine and alkali salts said solution containingalso copper powder.

5. Process for the manufacture of acrylic acid nitrile which comprisespassing acetylene together with hydrocyanic acid into an aqueous acidreacting solution prepared from cuprous chloride and ammonium chloride.

6. Process for the manufacture of acrylic acid nitrile which comprisespassing acetylene together with hydrocyanic acid into an aqueous acidreacting solution prepared from cuprous chloride and ammonium chloride.said solution containing also copper powder.

'7. Process for the manufacture of acrylic acid nitrile which comprisespassing acetylene together with hydrocyanic acid into an aqueous acidreacting solution prepared from 45.5 parts of cuprous chloride, 24.5parts of ammonium chloride, 42 parts of water and 2.85 parts ofconcentrated hydrochloric acid at a temperature of about 30 C.

8. Process for the manufacture of acrylonitrile which comprises bringingacetylene together with hydrocyanic acid into contact with an aqueousacid reacting solution of cuprous chloride, said solution containingalso a salt of the class consisting of ammonium and alkali metal salts.

9. The process of preparing acrylonitrile which comprises reactingacetylene and hydrocyanic acid in an acidic aqueous solution comprisingcuprous chloride and ammonium chloride as a solubilizer for the cuprouschloride.

10. The process as defined in claim 9 wherein the acid aqueous solutioncontains an amount of copper sufficient to maintain the copper chloridein the cuprous state.

11. The process of preparing acrylonitrile which comprises reactingacetylene and hydrocyanic acid in an aqueous solution of a cuproushalide as a. catalyst at a temperature within the range of to 103.

12. The process of preparing acrylonitrlle which comprises reactingacetylene and hydrocyanic acid in an aqueous solution of cuprouschloride as a catalyst at a. temperature within the range of "(0 to 103.

13. The process or preparing acrylonitrllo which comprises reactingacetylene and hydrocyanic acid in the presence of a catalytic solutionof a cuprous halide.

14. The process of preparing acrylonitrile which comprises reactingacetylene and hydrocyanic acid in the presence 01' an aqueous catalyticsolution of a cuprous halide.

15. The process or preparing acrylonitrlle which comprises reactingacetylene and hydroasses cyanic acid in the presence of an acidiccatalytic solution of a cuprous halide.

16. The process of preparing acrylonitrile which comprises reactingacetylene and hydrocyanlc acid in the presence of an acidic catalyticsolution of cuprous chloride.

17. The process for preparing acrylonitriie which comprises supplying toan aqueous acid reacting solution of cuprous chloride a mixture ofacetylene and hydrocyanic acid, said mixture containing a substantialexcess of acetylene.

18. The process for preparing acrylonitrile which comprises supplying toan aqueous acid reacting solution of cuprous chloride a mixture ofacetylene and hydrocyanic acid, said mixture containing a substantialexcess of acetylene and said solution 0/ cuprous chloride containingalso a salt of the class consisting of ammonium, amine and alkali salts.

19. The process for preparing acrylonitrile which comprises supplying toan aqueous acid reacting solution of cuprous chloride a mixture ofacetylene and hydrocyanic acid, said mixture containing a substantialexcess of acetylene and said solution 0! cuprous chloride containingalso (a)a salt of the class consisting of ammonium, amine and alkalisalts, and (b) copper powder.

20. The process for preparing acrylonitrile which comprises supplying toan aqueous acid reacting solution of cuprous chloride a mixture so559,734

of acetylene and hydrocyanic acid, said mixture containing approximately10 parts of acetylene per one part of hydrocyanic acid.

21. The process for preparing acrylonitrile which comprises s pplying toan aqueous acid reacting solution of cuprous chloride a mixture ofacetylene and hydrocyanic acid, said mixture containing approximately 10parts of acetylene per one part of hydrocyanic acid and said solution ofcuprous chloride containing also a salt Of the class consisting ofammonium, amine and alleali salts.

22. The process for preparing acrylonitrile which comprises supplying toan aqueous acid reacting solution of cuprous chloride a mixture ofacetylene and hydrocyanic acid, said mixture containing approximately 10parts of acetylene per one part of hydrocyanic acid and said solution ofcuprous chloride containing also (a) a salt 0] the class consisting ofammonium, amine and alkali salts, and (b) copper powder.

PETER KURTZ.

REFERENCES CITED The following references are of record in the file ofthis patent or the original patent:

FOREIGN PATENTS Country Date Germany Sept. 23. 19.22

Number Certificate of Correction Reissue No. 23,265 September 5, 1950PETER KURTZ It is hereby certified that error appears in the printedspecification of the above numbered patent requiring correction asfollows:

Column 4, line 17, after the word aqueous insert acid and that the saidLetters Patent should be read as corrected above, so that the same mayconform to the record of the case in the Patent Office.

Signed and sealed this 12th day of December, A. D. 1950.

THOMAS F. MURPHY,

Assistant Co mmisaioner of Patents.

